1. Field of the Invention
This invention relates to the processing of multifilament synthetic yarns, particularly polyester and nylon yarn, with fiber lubricants which are applied as spin-finishes subsequent to the extrusion of the fibers from the spinneret.
2. Description of the Prior Art
In the production of polyester and polyamide yarn, a lubricant is applied as a coating to the yarn after extrusion of the fibers. The lubricant is essential in order that the subsequent processing of the yarn can take place. The yarn is subsequently subjected to a texturing process in which the fibers are stretched or bulked after being heated such as by contact with a heated metal plate. In addition to lubricity properties required to avoid breaking the fibers during such processing, relatively high oxidation stability is required to avoid excessive oxidative degradation of the fiber lubricants applied to the yarn upon exposure to the temperatures encountered during this processing operation. Complete volatiization of the fiber lubricant which contacts the heated metal plate is desirable.
It is known to utilize polyoxyalkylene compounds as fiber lubricants to prevent fiber breakage during pin or disk texturing processes. Such polyoxyalkylene compounds including heteric polyoxyalkylene compounds derived from the random polymerization of polytetramethylene oxide (tetrahydrofuran) with either ethylene oxide or 1,2-propylene oxide and utilizing a monohydric alcohol as an initiator are known from Tanizaki et al, Japanese Patent Announcement No. 213-1977. Tanizaki et al teach away from the use of polyhydric alcohols as initiators in the preparation of said polyoxyethylene compound fiber lubricants. The preparation of heteric copolymers of tetrahydrofuran and a lower alkylene oxide is known from U.S. Pat. No. 3,425,999 and British Patent No. 854,958 wherein both monohydric and polyhydric alcohol initiators are disclosed for use in the preparation of the copolymers. In U.S. Pat. No. 4,038,296, there are disclosed heteric copolymers of said monomers prepared using monohydric alcohol initiators.
Ethylene oxide capped heteric copolymers of tetrahydrofuran and ethylene oxide are disclosed in copending application Ser. No. 909,879, filed May 26, 1978, now U.S. Pat. No. 4,198,464, and fiber lubricants prepared by the block polymerization of tetrahydrofuran and ethylene oxide are disclosed in copending application, Ser. No. 909,880, filed May 26, 1978. Block copolymers of ethylene oxide and butylene oxide are disclosed in U.S. Pat. No. 3,834,935.